Also, the thing about this type of high speed photography is that you're triggering the light source... so if you're trying to photograph something that creates its own light, these strobe-triggering devices are going to do you no good at all.

To do that, you'd need to trigger a high speed shutter, which is a lot harder to do.. there's usually a lag between when a shutter is triggered and when it actually takes a picture, and the mechanical shutters on most SLR's don't actually go much faster than 1/250s. The images you see of matches being struck and explosions happening and such are taken with motion picture cameras with very high framerates.

Although, with electronic shutters that are becoming more common, there might be a way to get actual shutter speeds of 1/8000s with minimal lag. Could be very cool.

Even better... Just open your camera's shutter and put your hand in front of the lens until you see a lightning strike beginning. Remove your hand for just the amount of time that you see lightning. Then, put your hand back without closing the shutter. Repeat for however long you want to leave the shutter open, say 30 seconds. If you capture a few lightning bolts this way, you end up with a shot that looks like Zeus was VERY angry.

6ms is long enough for something (like a balloon starting to pop) to happen.

Most people, if they try hard enough, can count to 10 aloud in 1 second. That means they are speaking with the capable thought around 100ms. Now, just imagine how high you can count in your mind, not speaking aloud, in 1 second. How many instant thoughts can you get? How many milliseconds is it to process the next number in your counting scheme for you?

Now try watching a baloon pop. Try capturing that moment where the shape is Juuuuust starting to rupture - even though it's no longer holding the air in. How fast do you think that went? It wasn't like 1ms, but it wasn't 100 either.

The big thing to consider is the technically difficult issue of trying to get the baloon to pop and take a picture based on "Light" - something I think the GP completely overlooked. The reason we use sound is because its easy to set up a trigger for that - because the trigger is actually the baloon popping, not our own specific timer. A baloon doesn't produce a flash of light when it pops - so you can't use light to set off your photo, unless you are trying to detect the difference in shape of the baloon on a really tiny scale and hope it sets off your radar triggers or something incredibly complex - because simply timing the photo with your needle doesn't always work.

Taking photos of lightening at night is very doable using this method. But not when you are trying to take some of the most beautiful lighting pictures... which occur during the day. Using your reflexes to time shutter open/close is more luck than skill.
Even at night, depending on the dSLR camera, the amount of time it takes for the camera to process a bulb setting and store the image can introduce long delays between shots, and missed opportunities. Bulb settings increase the noise in a shot the longer the shutter is open. Turning off the camera noise processor and doing it in Photoshop reduces in-camera processing time significantly, but it can introduce odd bits of color scattered around the photograph that require touchup.

That's why they sell lightening triggers that use the lightening flash itself to trigger the shutter. Camera lag is an issue, but not with the higher end cameras.

I only use the nighttime long-exposure method as the lightening triggers are a little pricey for my taste.